1. Field of the Invention
The present invention relates to a running control system of an automobile which runs the automobile at an optimum velocity and space relative to a forerunning vehicle.
2. Related Background Art
Conventionally, a great many efforts and practices have been made to develop component for cruising automobiles at constant velocities and constant car-to-car spaces to simplify driving operations. For example, Japanese Non-examined Patent Publication No. 7-47862 (1995) has disclosed a system which enables an automobile to cruise at a preset velocity or at an optimum car-to-car space without the driver""s foot on the accelerator pedal.
Further, Japanese Non-examined Patent Publications No. 7-225893 (1995) and No. 9-71154 (1997) have disclosed systems which automatically start and stop automobiles, freeing the drivers from frequent operations of the brake pedal and the accelerator pedal while the automobile is running slowly. Furthermore, Japanese Non-examined Patent Publication No. 10-166898 (1998) has disclosed a system which has two cruising modes (slow cruising mode and fast cruising mode) and switches between these modes to accomplish fast cruising at a preset car-to-car space and low cruising in heavy traffic conditions.
However, the conventional car-to-car space control systems have been designed to calculate an optimum car-to-car space from the velocities of the current and forerunning automobiles. Therefore, for example when finding a stationary object ahead, the automobile running at a high speed must reduce its velocity much earlier to keep an optimum space from the stationary object.
Further, when finding a stationary automobile ahead, the automobile running in the slow follow-up mode must control running to keep an optimum space from the stationary automobile.
Further, almost all drivers have wanted easier and simpler driving operations in all driving ranges.
The main purpose of the present invention is to provide a running control system for an automobile which enables cruising at an optimum car-to-car space by simple and easy driving operations in any driving range (from slow running in a heavy traffic status to fast running).
The aforesaid purpose can be accomplished by a running control system comprising nearby-object detecting component for detecting an object ahead of the automobile and calculating the space between the automobile and the object and the relative velocity of the object, component for detecting the velocity of the automobile, and component for automatically controlling the velocity of the automobile; wherein said running control system has at least two cruising modes such as a slow follow-up mode and a fast follow-up mode and lets said velocity controlling component control the velocity of the automobile to keep a preset constant space between the automobile and an object detected by said nearby object detecting component in the slow follow-up mode or to keep a preset constant space between the automobile and only one of objects detected by said nearby object detecting component that is faster than a preset ground velocity in the fast follow-up mode.
Further the purpose can be accomplished by a running control system which can automatically switch to the slow follow-up mode when the target velocity of the fast-running automobile goes under a preset velocity and cancel the maximum velocity in the slow follow-up mode manually by the driver.
In accordance with the present invention, an automobile running control system having xe2x80x9cFast follow-upxe2x80x9d and xe2x80x9cSlow follow-upxe2x80x9d modes can cruise the automobile at an optimum car-to-car space in all running ranges (from slow cruising in a heavy traffic condition to fast cruising) by controlling the velocity of the automobile so that the current automobile may keep an optimum space from the detected forerunning object which is faster than the preset ground velocity in the xe2x80x9cFast follow-upxe2x80x9d mode. When the fast follow-up velocity of the automobile falls under the preset velocity, the system automatically enters the xe2x80x9cSlow follow-upxe2x80x9d mode, which reduces the driver""s burden.
Further, the safety and convenience of the automobile can be improved and assured when the system is equipped with a means which suppresses cruising at a velocity higher than a preset velocity limit when the target velocity goes higher than the preset velocity limit and enables manual cancellation of cruising at a high-limit velocity.